The present invention relates to a hidden pump housed in a seat tube of a bicycle and taken out with ease and speed. The pump is integrally assembled with a bicycle saddle. A coupling tube is downwardly extended from a saddle mount of a saddle with a cylinder tube removably connected to the coupling tube. In the cylinder tube is slidably housed a pumping rod and a flexible air duct used to connect the pump to a tire is received in the hollow pumping rod. The pumping rod can be slidably operated in the pump tube to compress air into a tire. The pump assembly can be quickly housed in a seat tube of a bicycle and be locked in place by a quick locking means.
When a tire of a bicycle becomes flat in the middle of riding, it is rather difficult for a person to locate a pump for inflation. In general, a bicycle itself is not equipped with a pump and a person must secure an extra bulky pump to somewhere on the bicycle when riding a long distance. Otherwise, a person must bring a bicycle with a flat tire to a bicycle shop for repair and inflation. Fixing such a bulky pump to a bicycle may cause inconvenience to the operation of the same in one aspect and the exposure of such a pump spoils the outer look of a bicycle in another aspect.